The present invention relates to a closure fixture, preferably to a slide member or a valve for radioactive and toxic media, provided with a fixture housing, a housing cover connected to the housing via a sealing surface, and a closure device with drive means arranged on the housing cover.
Many different types of closure fixtures are known. In this connection, linear and pendulum slide members are preferred, and in particular pendulum slide members are characterized by a very compact structure with regard to their drive mechanism as DT-OS No. 25 11 591.
In the case of closure fixtures for radioactive and/or toxic gases, special safety measures have to be taken when effecting repairs on account of wear or destruction of an operating part. All operating parts and thus also parts subjected to wear and tear which come into contact with a radioactive or toxic medium must first of all undergo a special cleaning process before they can be handled in the usual way. During the removal of internal operating parts from the fixture housing, protective clothing, breathing apparatus and other safety devices must be employed, and in addition there is the danger of contamination of the surrounding environment. In order to prevent such contamination special protective tents or chambers have to be erected in some cases over the fixtures being repaired.
In order to reduce the resultant difficulties during repair work, dismantling devices are used in special cases, especially with reactors, which are adapted to the local conditions and form a type of protection room with manipulating devices employed in the region of the fixture being repaired. Such dismantling devices are designed as assembly aids and must be adapted to the existing constructional parts of the plant. This has the resultant disadvantage that they are generally extremely complicated and cannot be universally used, and on the one hand are expensive to supply and on the other hand are difficult to maintain and operate.